In conventional computers and word processors, identification of the characters input through a keyboard or identification of the characters that have been specified through some sort of input is realized by allocating a character code specific to each character. The character codes of normally used characters is standardized. Further, data compatibility between various types of computers and softwares is maintained when document files are being processed.
Although the character codes have been standardized, the character typeface (i.e. the font) displayed on the basis of these character codes exists in a variety of forms. Accordingly, when the characters are output to an output device, i.e. displayed on a display device or printed using a printer, in addition to the role as communication of information, the characters are used to impart a visual effect. Due to the increasing use of personal computers, recent years, in particular, have seen a simplification of DTP (desktop publishing) which has led in turn to an increased demand for a variety of types of font data.
Font data is generally supplied in a state where it has been written to a font memory such as exclusive ROM (Read Only Memory) or a storage medium such as a CD-ROM or the like. Further, fonts are classified into outline fonts and bitmap fonts based on the difference in the data format. Bitmap fonts are formed from a dot pattern that represents characters by the arrangement of the dots on a matrix. The font output result is obtained by the final output of this dot pattern on a display device or printer.
On the other hand, bitmap fonts require different data corresponding to each font size. Therefore, a great deal of data is needed to match the plurality of sizes. In contrast, outline fonts are formed in a template representing an outline using several points and lines joining the points. While it is possible to provide a plurality of sizes, a calculation is required to expand the font data in order to obtain the actual font pattern.
Moreover, the aforementioned font memory is usually built into a printer. Accordingly, instead of outputting the dot pattern sent from a computer or the like, output becomes possible by creating or extracting a dot pattern from the printer's own font memory according to the specified character code and font type. In this case, it is normal to built-in an exclusive font processing controller into the printer enabling a font to be output at a faster speed than if the font calculation processing were performed in the computer.
However, in case of the bitmap font, even for a font of same type and size, the quality of the font obtained differs depending on the specifications, and particularly on the resolution, of the destination display device or printer. For example, the design of a font output from respective printers or display devices having different resolutions is different.
Furthermore, after the expansion calculation for an outline font, it too is processed as a dot pattern resulting in it also having the same problems as a bitmap font. In addition, because an outline font requires a calculation processing, a load is placed on the CPU of the computer which then places a burden on the processing of other tasks by the CPU.
Moreover, in a computer and the like, when font data is used directly from a storage medium such as a CD-ROM or the like, or when it is installed on a built-in magnetic disk or the like and used, processing is required to access the storage medium or the magnetic disk. This access processing takes a far longer time than when the aforementioned font memory is used and is a main factor in slowing the output to a display device or printer.
Furthermore, when the font memory built into a printer is used, even if the font is the same size and same type, generally, font data defined specifically by that printer manufacturer is stored in the font memory and it is often the case that a font is output in a pattern slightly different from the font pattern displayed on the display device.
Moreover, because it is possible to confirm the approximate layout of a character on the display device, this is sufficient for most uses. It is usually only necessary to display a high quality font in an output result obtained when printing using a printer. However, when a high resolution, large sized display device is used, or when it is necessary to enlarge the display of a character on the display device, it is desirable for a font with a smooth outline to be displayed. Accordingly, there is a demand for a font memory capable of outputting font data of different resolutions to comply with the purpose of the use and the application.